Electrical selector for coin chutes



April 27, 1943.

B. A. ANDALlKlEWlCZ ETAL ,317,351

ELECTRICAL SELECTOR FOR COIN CHUTES Filed Oct. 25. 1940 2 Sheets-Sheet 1 Ba/e r62 2 BY April 27, 1943. B. A. ANDALJKIEWICZ 'Er A|.

ELECTRICAL SELECTOR FOR GOIN CHUTES Filed Oct. 2.5, 1940 2 sheets-sheet 2 OHNEY.

Patented Apr. 27, 1943 UNITED STATES PATENT OFFICE 2,317,351 ELECTRICAL snmc'ron. FOR com CHUTES Boley A. Andalikiewlcz and Drexel T. Carlson, Kansas City, Mo., uslgnors to 0. Earl Hovey,

, Kansas City,Mo.

Application October 25, 1940, Serial No. 362,118

Claims. (01. 194-100) This invention relates to coin detecting and slug ejecting apparatus of electrical type intended for use in combination with coin chutes, and the primary object isto provide positive, eflicient and inexpensive apparatus capable of being included as a part of machines, the operation of which depends upon the insertion of genuine coins of predetermined value.

This invention has for a salient object, the provision of an electrical coin selector for coin chutes which tests the coin introduced thereto byanalyzing its frequency of vibration and converting sound vibrations of the coin into electrical impulses, the nature of which controls the position oi a diverting means, to the end that genuine coins of certain types are directed to a coin receiving box while spurious coins and/or slugs are rejected.

Another important object of this invention is to provide electro-mechanical means for estab lishing vibrations and utilizing such vibrations to operate diverting means disposed in the path of travel, for the purpose of definitely and accurately detecting the nature of a coin introduced into the means and thereby directing the coin along a normal path of travel or through a branch thereof.

A yet further object of this invention is to provide an electrical selector for coin chutes, having as a component part thereof, means for establishing and detecting vibration frequencies of coins and thereafter employing such vibrations to operate electrically controlled parts for establishing the path of travel of the coin whereby the latter is diverted if of a spurious nature.

This'invention has for a. more specific object than those above set down, the provision of coin testing apparatus of a nature employing an electrical circuit having appropriate parts for ampl fylng electrical impulses and for handling such impulses in a way that is directly related to the sound vibrations of the coin whereby selection is positively and accurately made.

Other objects of the invention as well as speciflc details of construction that are preferably employed in producing commercial forms of selectors embodying the concepts of the present invention, will appear during the course of the following specification, referring to the accompanying drawings wherein:

Figure 1 is a side elevational view of a. selector for coin chutes illustrating the same entirely removed from association with any apparatus.

Fig. 2 is an edge elevational view of the selector ior coin chutes.

Fig. 3 is a top plan view of the selector illustrated in Fig. 1.

Fig. 4 is a fragmentary sectional view taken on line IV-IV oi Fig. 1;' and Fig. 5 is a wiring diagram illustrating an electrical circuit usable with parts of the selector shown in Figs. 1 to d inclusive.

The numeral ii designates a section of a coin chute forming a, part of the selector that is carried by a. suitable frame it upon which is mounted the directional microphone, generally indicated by the numeral 52 and having a conventional reflector for collecting sound waves.

An anvil Ml having an inclined face it is rigidly secured to frame is through the medium of a clamp or the like iii, it being important that this anvil id be rigid and solid enough to establish .ing 64.

vibrations in the coin when the same is dropped from the end or section 8 of the coin chute disposed the proper distance above surface l6.

Hopper as has one wall thereof lined with soft substance 22 against which the coin impinges when it rebounds from anvil id. Substance 22 must be employed to eliminate conflicting vibrations that might be picked up by microphone ii. Hopper 522i merges into an outlet conduit 24 in vertical alignment with coin box it. This coin box is usually positioned where unauthorized persons cannot reach. the same-and where only the operator of the mechanism with which the coin chute is combined, may empty the same from time-to-time.

A branch 28 in communication with conduit 2% terminates in a reject stall 3t through which passes spurious coins, slugs or the like.

Solenoid 32 mounted on a part of frame 5!) has a reciprocable core 36 normally disposed in conduit 2d traversing the path of travel for all coins entering chute 8.

Microphone 52 picks up the sound vibrations of the coin and in the preferred manner of constructing the selector, microphone 62 will resonate at the frequency of the coin and. creates electrical impulses which enter the circuit, diagrammatically shown ln Fig. 5.

Generally speaking, the circuit comprises an amplifier tube as, a second amplifier tube 38, and a relay control tube iii. These three tubes as well as hand reject filter Q2 are contained in hous- Two relays t6 and it respectively are likewise in the circuit as is a coin operated switch, generally designated by the numeral 50. This latter switch is provided with a resilient contact member 52. the free end below the end of outlet conduit 24 to be struck of which is immediately impulses from a spurious coin,

.by a coin prior to its dropping into box 26.

Microphone I2 is in connection with tube 36 through the medium of wires 54 and 56 and through wires 58 and 68. A grid leak resistor 62 is shunted across the microphone I2.

Heater voltage from an alternating current source or a battery is supplied to tubes 36, 38 and 48 through wires 62-64, 66-68 and 'I8I.2 respectively. Wires I4 and I6 extend from a source of B current to tubes 36, 38 and 48. Band reject filter 42 is shunted across tubes 36 and 38 and comprises an adaptation of the Wiens bridge. This bridge is so used that no potential difference will exist across said bridge at points where the same is connected to tubes 38 and 36 respectively, when energy coupled back from tube 38 is of the same frequency as that to which the bridge is balanced. It therefore follows that when the bridge is balanced for a specified frequency, input of electrical currents of the specified frequency to the bridge will not result in the introduction of any potential on the part of tube 36. Conversely the bridge will be unbalanced and serve to pass currents of all other frequencies. Condensers I8, 88 and 82 are in filter 42 as are resisters 84, 86 and 88. Coupling condensers 98, 82 and 84 should be used and plate load resisters 88 and I80 are employed in conventional manner. Grid leak resistors 88 and 88 are connected in conventional fashion. Resistors 9| and 99 are conventional cathode biasing resistors. Resistor 95 is a conventional dropping resistor in the screen grid circuit of the tube 36. Condenser 93 by-passes the screen grid of tube 36 to its cathode. Condenser 91 is a conventional cathode by-pass around resistor 98. 7

Relay 46 has condenser I82 in circuit therewith to by-pass current impulses for the purpose of preventing chatter. This relay 46 has its armature I04 normally attracted to maintain the circuit supplying energy to relay 48 in an open condition. Armature I86 of relay 48 however is normally released until the coil I88 thereof is energized to draw armature I06 against contact point II8.

Solenoid 32 is diagrammatically shown in circuit with relay 48 and the connections thereto are clear and will become more thoroughly understood during the description of the operation of the selector to be hereinafter set' down.

Assume that a genuine coin is dropped into chute 8. The distance of fall by gravity should be great enough to set up, in the coin, vibrations sufficient to cause the microphone I2 to create electrical impulses of the same frequency. These impulses are introduced into the control grid circuit of tube 36, and the output of said tube is amplified by the tube". The output of tube 38 is fed into relay control tube 40, and also a por tion of the output of tube 38 is fed back' through filter 42 to the cathode and suppressor grid of cathode biased tube 36. When the frequencies frequencies of a proper coin, that subsequently reach tube 48, control the flow of current to relay 46 to de-energize the same. microphone I2 that is passed to the grid of tube 48 when genuine coins are employed, after having been amplified by tubes 36 and 38,*result in an amperage drop in the plate circuit supplying current to relay 46. This obtains because tube 48 has no cathode bias resistor or other source of bias voltage, and is therefore, operated at zero bias. This manner of operation results in tube 48 drawing its maximum plate current when no Y input potential is present on its grid. The presence of an alternating input potential on the grid will cause the plate current to drop on the negative portion of the cycle, and remain unchanged on the positive portion of the cycle. The net effect will be a reduction in plate current. The de-energization of relay 46 then occurs because of the drop in plate current, and armature I84 is released to strike contact point I I2. Theclosing of the circuit supplying power relay 48 from lines H4 and H6 will cause relay 48 to close armature I86 and contact points :I0.

Switch 68 being always normally closed, is in this circuit, which may be traced as follows:

Line II4 through closed switch 58, wire II8, wire I28, coil I88, wire I22, wire I24, armature I86, wire I26 and wire I28 to line II6.

Obviously the coil of solenoid 32 will be energized through the following circuit:

of a genuine coin are generated at the microphone, no voltage exists across the bridge and therefore, no bucking current will pass to the cathode and suppressor grid of tube 36. It is to be noted that the arrangement of the circuit is such that voltages across the bridge, caused by phase with the voltage on the cathode and suppressor grid; and that this condition will prevent further amplification by tubes 36 and 38 when the output of the bridge is coupled back to the resistance biased cathode of tube 36.

Amplified electrical impulses generated by the are out of v From line I I6 through wires I28 and I26, armature I86, wire .I24, wire I30 to solenoid 32, thence through wire I32, wire H8 and closed switch 58 to line I I4.

Such electrical action in the system will withdraw core'34 from within the passage formed by outlet conduit 24 and permit the good or authorizedcoin to drop directly into coin box 26-. As the coin drops, it will strike member 62 of switch 50 and momentarily open the circuit just traced to cause armature I86 to return to the position shown in Fig. 5, where core34 is in the normal position barring the passage of coins through conduit 24.

The momentary passage of current from microphone I2 to relay control tube 48 will have passed and the current that was altered by the flow of energy to the grid of tube 40 will return to its normal condition to energize relay 46 and again withdraw armature I84 from contact point II2.

Microphone I2 is of the crystal type that establishes a current'and which has a resonance point. This microphone should resonate at the frequency of the coin selected by the user to be that which is, of the proper denomination and which should be allowed to pass into coin box 26.

The description just set down as to .the manner in which a coin of predetermined type is allowed to pass into box 28 through conduit 24, indicates to a large degree, what .occurs when a slug or spurious coin is introduced into chute I. As is the case with coin I34 any slug will strike inclined face I8 of anvil I4 to establish a strain within the coin or member I34 and thereby insure vibrations that will be picked up by microphone Coin I34 is in a plane substantially parallel to the face of microphone I2 and therefore, the

mechanical vibrations-created immediately adjacent to microphone I2 will create sound waves that will be pomtively picked up.

An improper coin will have the sound vibrations thereof picked up by microphone I2 for conver- The current from lify the impulses on the first tube and to prevent an action on tube 40. A certain portion of the current passes however, to tube 40 and hence results in a slight change in the current flow through relay 46 but does not effect the setting thereof. Relay 48 is therefore allowed to remain as shown in the diagram of Fig. 5, and therefore, core 34 of solenoid 32 remains stationary to be struck by the slug or spurious coin for diversion into passage 28'and thence through reject stall 30.

From the above it is to be noted that filter 42 receives and conducts a part of the current-to, tube 38 when a slug is dropped through chute 8 and because filter 42 is arranged to allow the flow of current of all impulses but those of a frequency of the proper coin the amplifying action of tubes 36 and 38 will be held to a very low I gain level.

Tubes 36, 38 and 40 are of commercial type and when the circuit is established as indicated by Fig. 5, the results obtained with respect to dropping proper predetermined coins and coins or units other than that of selected value will be as mentioned.

It is vital to the successful operation of the selector that the vibrations of the coin or other device dropped through chute 8, be converted into electrical impulses and that no part of the mechanism be allowed to vibrate to efiect the action of microphone i2 nor the parts associated therewith.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is: j

1. In an electrical selector for coin chutes, a conduit providing a path of travel for coins to a point of discharge; means having .an element normally in the path for directing spurious types of coins from the path to prevent them frompassing to the point of discharge; a rigid anvil disposed to be struck by coins moving in said path; a microphone adjacent to the anvil to pick up sound vibrations of the coin when it strikes the anvil; and means operable by the electrical impulse output of said microphone to withdraw the diverting means element from the path when genuine types of coins are sent along the path.

2. In an electrical selector for coin chutes, a conduit providing a path of travel for coins to a point of discharge; means having an element normally in the path for diverting spurious types of coins from the path to prevent them from 3. In an electrical selector for coin chutes, a

conduit providing a path of travel for coins to a point of discharge; means having an element normally in the path for directing spurious types of coins from the path to prevent them from passing to the point of discharge; a rigid anvil disposed to be struck by coins moving in said path; a, microphone adjacent to the anvil to pick up sound vibrations of the coin when it strikes the anvil; and means operable by the electrical impulse output of said microphone to withdraw the diverting means element from the path when genuine typesv of coins are sent along the path, said anvil having a face inclined with respect to the path of travel of the coin to cause the latter to strike at a point on the meeting edge between one face and the annular side thereof.

4. In an electrical selector of the character described for eliminating slugs, structure providing a path of travel for coins to a point of discharge; an element causing all coins to vibrate while in said path; parts responsive to the vibrations of genuine coins; an element for diverting slugs from the path to prevent them from passing to the point of discharge; and means controlled by the responsive parts to operate the diverting means. 7

5 In an electrical selector of the character described for eliminating slugs, structure providing a path of travel for coins; an element causing all the coins to vibrate while in said path; a resonant microphone responsive to the frequencies of vibration of the genuine coins;

an element for diverting slugs from the path to prevent them from passing to the point of discharge; and means controlled by the resonant microphone to operate the diverting means.

6. In an electrical selector of the character described for eliminating slugs, structure providing a path of travel for coins; an element causing all the coins to vibrate while in said path; a resonant microphone responsive to the frequencies of vibration of the genuine coins; an amplifier for increasing the output of the resonant microphone; an element for diverting slugs from the path to prevent them from passing to the point of discharge; and means controlled by the resonant microphone and amplifier to operate the diverting means.

7. In an electrical selector of the character described for eliminating slugs, structure providing a path of travel for coins; an element causing all the coins to vibrate while in the said path; a microphone; a selective amplifier for increasing theoutput of the microphone that is responsive to the frequencies of vibration of the genuine coin; an element for diverting slugs from the path to prevent them from passing to the point of discharge; and means controlled by the microphone and amplifier to operate the diverting means.

8. In an electrical selector of described for eliminating slugs, structure providing a path of travel for the coins; an element causing all the coins to vibrate while in said path; a resonant microphone responsive to the frequencies of vibration of the genuine coins; a selective amplifier for increasing the output of the microphone that is responsive to the frequencies of the genuine coins; an element for diverting slugs from thepath to prevent them from passing to the point of discharge; and means controlled by the resonant microphone and amplifier to operate the diverting means.

9. In' an electrical selector for coin chutes, a conduit providing a path of travel-for coins to a point of discharge; means having an element normally in the path for directing spurious types of coins from the'path to prevent them from passing to the point'of discharge; a rigid anvil the character disposed to be struck by coins moving in said path; a resonant microphone adjacent to the anvil to pick up sound vibrations of the coin when it strikes the anvil; and means operable by the electrical impulse output of said microphone to withdraw the diverting means element from the path when genuine coins are sent along the path.

10. In an electrical selector for coin chutes, a conduit providing a path of travel for coins to a. point of discharge; means having an element normally in the path for diverting spurious types of coins from the path to prevent them from passing to the point of discharge; a rigid anvil disposed to be struck by coins moving in said path; a microphone adjacent to the anvil to pick up sound vibrations of the coin when it strikes the anvil; a selective amplifier for amplifying the output of the microphone that is responsive to the frequencies of the genuine'coins; and means operable by the amplifier to withdraw the diverting means element from the path when genuine 10 coins are sent along the path.

BOLEY A. ANDALIKIEWICZ. DREXEL T. CARLSON. 

